Copper-indium-gallium-sulfur/selenium (CIGS) materials are commonly used as the absorber in thin film solar cells. One approach to producing a CIGS absorber in thin film solar cell technology is to successively deposit elemental layers of the copper, indium, gallium and sulfur, followed by an annealing step (for example in a selenium environment).
One challenge in this fabrication process is to maintain adhesion between the deposited layers. Namely, the layers being formed from different materials will have different coefficients of thermal expansion. During the heating and cooling cycles of absorber fabrication, the differing amounts of volume expansion can cause the layers to delaminate. This delamination problem is a significant roadblock to large-scale implementation of CIGS thin film solar cell production.
Thus, techniques for fabricating CIGS thin film solar cells that minimize or eliminate such adhesion problems would be desirable.